View Full Version : lapstrake frames question

ricardo de oliveira
05-11-2005, 07:40 PM
Suppose you had just finished planking a traditional lapstrake boat. All those rivets. Just flipped the hull and now you're going to steam bend the frames inside. Question: Where do you clamp them? How? No ribands. Weights? Screws? Bars from the ceiling? How? How? My gloves are burning...

05-12-2005, 06:47 AM
I believe the normal routine is to rivet them while still hot, no clamping needed. If you can't do that then you'd have to clamp at the shear & brace from above if needed.

05-12-2005, 07:55 AM
Last boat I worked on, we clamped them along the sheer strake (or the one below). A clamp on each side. The rib can be forced downward to take the shape of the planking. Then start riveting in the bottom of the boat.

I found that a couple of rivets did the job to hold the rib down, and allows you to get on to the next one. (which is probably ready in the steam box) This way, you can get into a rhythm with your helper, and get a decent number done in one work session.

Chadd Hamilton
05-12-2005, 08:08 AM
I too use the technique WWheeler describes. I usually get by with one clamp on the sheer and a few rivets to secure the rib before moving to the next one.


ricardo de oliveira
05-12-2005, 09:43 AM
I was thinking in some way of pre-fitting,while the thing cool and dries, so one can apply some varnish or paint in the inside face of the frame before permanent riveting.

Bruce Hooke
05-12-2005, 10:03 AM
How about drilling for a couple of rivits but instead of installing rivits right away use small machine screws (bolts) that can be undone once the frame has cooled?

Tom Robb
05-12-2005, 10:16 AM
Yes, it's a bit of a fire drill, but rivit them while hot. Start the rivits just into the plank so they're ready and hammer them home before the thing cools. Once the copper nail is through the frame you. or one of the gang, can begin setting the roves. The nail ought to hold the frame in place without the rove so there's no need to rush that part.

Ray Weber
05-12-2005, 11:38 AM
A few years ago Harry Bryan did an artical in WB on how to make what he called Crab Clamps. He used them to hold the strakes in place, but since you would be making them they could be custom made for your application. R

Thad Van Gilder
05-12-2005, 11:44 AM
I use drywall screws at each of the laps.


Paul Scheuer
05-12-2005, 12:40 PM
If bracing from the overhead isn't an option, a scrap of wood under C clamps at the sheer will provide an additional pressure point nearer the bilge. I've only used this on models (it's a long to the overhead ;) , but it should work. Tapping on the end of the rib while the clamp is being adjuested will also help to get the rib to match the planking.